The entire contents of Japanese Patent Application No. 9-119640 filed on May 9, 1997 are incorporated herein by reference.
The present invention relates to a computer system and, more particularly, to a computer system having a function of preventing overheating of devices in the system.
In recent years, various portable laptop type or notebook type personal computers that can be driven by batteries have been developed. Such personal computers use higher-performance CPUs, and the users can easily acquire a comfortable use environment.
However, as the performance of the CPU is improved, the amount of heat generated by the CPU increases to cause troubles. More specifically, the internal temperature of the computer may have exceeded the operation guarantee temperatures of other members due to heat generated by the CPU, or the CPU itself may cause operation errors by that heat.
To solve such problems, recently, a method of monitoring the temperature of the CPU using a temperature sensor disposed near the CPU, and cooling the CPU using a cooling fan when the heat generated is considerable is used. In this case, when the CPU temperature has reached a fan rotation start temperature set in advance, the rotation of the cooling fan is started to cool the CPU. When the CPU temperature falls below a fan rotation stop temperature set in advance, the rotation of the cooling fan is stopped.
In a personal computer, in practice, the CPU is not the one and only heat source, and for example, a hard disk drive, PC card controller, and the like generate heat at considerably high temperature.
However, since the conventional cooling control method using a cooling fan uses only one temperature sensor, when the CPU temperature falls, the rotation of the fan is stopped even when other devices such as the hard disk drive, PC card controller, and the like are overheated. For this reason, the hard disk drive, PC card controller, and the like cannot be sufficiently cooled.
This problem can be solved to some extent by setting the fan rotation start temperature, i.e., the CPU temperature that starts fan rotation, at a sufficiently low temperature. In this case, even when the temperatures of the hard disk drive and PC card controller are low and they need not be cooled, the fan is rotated, thus increasing consumption power and noise due to wasteful fan rotation.
Note that another conventional cooling control method uses a plurality of temperature sensors, but does not perform cooling control in correspondence with heat sources. More specifically, the fan is controlled stepwise with respect to the entire housing, but no cooling control in units of heat sources is done. For this reason, the conventional cooling control method cannot perform optimal cooling control for the individual devices having different heat generation amounts.